How far can you see? The Andromeda Galaxy, 2.5 million light years away, is the most distant object easily seen by the unaided eye. Other denizens of the night sky, like stars, clusters, and nebulae, are typically hundreds to thousands of light-years distant. That’s far beyond the Solar System but well within our own Milky Way Galaxy. Also known as M31, the external galaxy poses directly above a chimney in this well-planned deep night skyscape from an old mine in southern Portugal. The image was captured in a single exposure tracking the sky, so the foreground is slightly blurred by the camera’s motion while Andromeda itself looms large. The galaxy’s brighter central region, normally all that’s visible to the naked-eye, can be seen extending to spiral arms with fainter outer reaches spanning over 4 full moons across the sky. Of course in only 5 billion years or so, the stars of Andromeda could span the entire night sky as the Andromeda Galaxy merges with the Milky Way. via NASA https://ift.tt/3wVUPFH

Grand design spiral galaxy Messier 99 looks majestic on a truly cosmic scale. This recently processed full galaxy portrait stretches over 70,000 light-years across M99. The sharp view is a combination of ultraviolet, visible, and infrared image data from the Hubble Space Telescope. About 50 million light-years distant toward the well-groomed constellation Coma Bernices, the face-on spiral is a member of the nearby Virgo Galaxy Cluster. Also cataloged as NGC 4254, a close encounter with another Virgo cluster member has likely influenced the shape of its well-defined, blue spiral arms. via NASA https://ift.tt/3d8S7od

How do stars form? Most form in giant molecular clouds located in the central disk of a galaxy. The process is started, influenced, and limited by the stellar winds, jets, high energy starlight, and supernova explosions of previously existing stars. The featured video shows these complex interactions as computed by the STARFORGE simulation of a gas cloud 20,000 times the mass of our Sun. In the time-lapse visualization, lighter regions indicate denser gas, color encodes the gas speed (purple is slow, orange is fast), while dots indicate the positions of newly formed stars. As the video begins, a gas cloud spanning about 50 light years begins to condense under its own gravity. Within 2 million years, the first stars form, while newly formed massive stars are seen to expel impressive jets. The simulation is frozen after 4.3 million years, and the volume then rotated to gain a three-dimensional perspective. Much remains unknown about star formation, including the effect of the jets in limiting the masses of subsequently formed stars. via NASA https://ift.tt/3zM1yUq

How are jets created during star formation? No one is sure, although recent images of the young star system HD 163296 are quite illuminating. The central star in the featured image is still forming but seen already surrounded by a rotating disk and an outward moving jet. The disk is shown in radio waves taken by the Atacama Large Millimeter Array (ALMA) in Chile, and show gaps likely created by the gravity of very-young planets. The jet, shown in visible light taken by the Very Large Telescope (VLT, also in Chile), expels fast-moving gas — mostly hydrogen — from the disk center. The system spans hundreds of times the Earth-Sun distance (au). Details of these new observations are being interpreted to bolster conjectures that the jets are generated and shaped, at least in part, by magnetic fields in the rotating disk. Future observations of HD 163296 and other similar star-forming systems may help fill in details. via NASA https://ift.tt/3qgasFi

Why does this galaxy have such a long tail? In this stunning vista, based on image data from the Hubble Legacy Archive, distant galaxies form a dramatic backdrop for disrupted spiral galaxy Arp 188, the Tadpole Galaxy. The cosmic tadpole is a mere 420 million light-years distant toward the northern constellation of the Dragon (Draco). Its eye-catching tail is about 280 thousand light-years long and features massive, bright blue star clusters. One story goes that a more compact intruder galaxy crossed in front of Arp 188 – from right to left in this view – and was slung around behind the Tadpole by their gravitational attraction. During the close encounter, tidal forces drew out the spiral galaxy’s stars, gas, and dust forming the spectacular tail. The intruder galaxy itself, estimated to lie about 300 thousand light-years behind the Tadpole, can be seen through foreground spiral arms at the upper right. Following its terrestrial namesake, the Tadpole Galaxy will likely lose its tail as it grows older, the tail’s star clusters forming smaller satellites of the large spiral galaxy. via NASA https://ift.tt/35LWnWB

Today the Sun reaches its northernmost point in planet Earth’s sky. Called a solstice, many cultures mark this date as a change of seasons — from spring to summer in Earth’s Northern Hemisphere and from fall to winter in Earth’s Southern Hemisphere. Precisely, the single time of solstice occurs today for some parts of the world, but tomorrow for other regions. The featured image was taken during the week of the 2008 summer solstice at Stonehenge in United Kingdom, and captures a picturesque sunrise involving fog, trees, clouds, stones placed about 4,500 years ago, and a 4.5 billion year old large glowing orb. Even given the precession of the Earth’s rotational axis over the millennia, the Sun continues to rise over Stonehenge in an astronomically significant way. via NASA https://ift.tt/3zEO2lC

Nights grow shorter and days grow longer as the summer solstice approaches in the north. Usually seen at high latitudes in summer months, noctilucent or night shining clouds begin to make their appearance. Drifting near the edge of space about 80 kilometers above the Earth’s surface, these icy clouds were still reflecting the sunlight on June 14. Though the Sun was below the horizon as seen north of Forrest, Manitoba, Canada, they were caught in a single exposure of a near midnight twilight sky. Multiple exposures of the foreground track the lower altitude flash of fireflies, another fleeting apparition shining in the summer night. via NASA https://ift.tt/3xxQEzL

Atmospheric refraction flattened the solar disk and distorted its appearance in this telescopic view of an Atlantic sunrise on June 10. From Belmar, New Jersey on the US east coast, the scene was recorded at New Moon during this season’s annular solar eclipse. The Moon in partial silhouette gives the rising Sun its crescent shape reminding some of the horns of the devil (or maybe a flying canoe …). But at its full annular phase this eclipsed Sun looked like a ring of fire in the heavens. June’s annular solar eclipse followed on the heels of the total lunar eclipse of late May’s Full Moon. Of course, that total lunar eclipse was a dramatic red Blood Moon eclipse. via NASA https://ift.tt/3zy7YGB

NGC 6888, also known as the Crescent Nebula, is a about 25 light-years across blown by winds from its central, bright, massive star. A triumvirate of astroimagers ( Joe, Glenn, Russell) created this sharp portrait of the cosmic bubble. Their telescopic collaboration collected over 30 hours of narrow band image data isolating light from hydrogen and oxygen atoms. The oxygen atoms produce the blue-green hue that seems to enshroud the detailed folds and filaments. Visible within the nebula, NGC 6888’s central star is classified as a Wolf-Rayet star (WR 136). The star is shedding its outer envelope in a strong stellar wind, ejecting the equivalent of the Sun’s mass every 10,000 years. The nebula’s complex structures are likely the result of this strong wind interacting with material ejected in an earlier phase. Burning fuel at a prodigious rate and near the end of its stellar life this star should ultimately go out with a bang in a spectacular supernova explosion. Found in the nebula rich constellation Cygnus, NGC 6888 is about 5,000 light-years away. via NASA https://ift.tt/2S8Qf7W

If Scorpius looked this good to the unaided eye, humans might remember it better. Scorpius more typically appears as a few bright stars in a well-known but rarely pointed out zodiacal constellation. To get a spectacular image like this, though, one needs a good camera, a dark sky, and some sophisticated image processing. The resulting digitally-enhanced image shows many breathtaking features. Diagonal across the image right is part of the plane of our Milky Way Galaxy. Visible there are vast clouds of bright stars and long filaments of dark and intricate dust. Rising vertically on the image left are dark dust bands known as the Dark River. Several of the bright stars on the left are part of Scorpius’ head and claws, and include the bright star Antares. Numerous red emission nebulas, blue reflection nebulas, and dark filaments became visible as the deep 17-hour expo image developed. Scorpius appears prominently in southern skies after sunset during the middle of the year. via NASA https://ift.tt/3gFCsOc